Thin-walled vacuum chamber machining method and arcuate bifurcated thin-walled vacuum chamber

Abstract

The present application relates to the technical field of vacuum chamber processing, and particularly relates to a thin-wall vacuum chamber processing method and an arc-shaped bifurcated thin-wall vacuum chamber. The thin-wall vacuum chamber processing method comprises the following steps: processing and treating a thin-wall pipe; fixing the thin-wall pipe and a mold; firstly performing air burning treatment on the thin-wall pipe, and then placing the thin-wall pipe into a vacuum brazing furnace to perform vacuum brazing; and assembling and welding the thin-wall pipe and an ultrahigh vacuum flange. The arc-shaped bifurcated thin-wall vacuum chamber comprises a vacuum chamber main body, and the vacuum chamber main body comprises: a first vacuum chamber, which constitutes a part of the length direction of the vacuum chamber main body, and the first end of the first vacuum chamber is used as one end of the vacuum chamber main body and is provided with one ultrahigh vacuum flange; a second vacuum chamber and a third vacuum chamber, which are connected to the end of the first vacuum chamber, and the second vacuum chamber and the third vacuum chamber jointly constitute the remaining part of the length direction of the vacuum chamber main body, and the ends of the second vacuum chamber and the third vacuum chamber are jointly provided with another ultrahigh vacuum flange.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum chamber processing, in particular to a thin-walled vacuum chamber processing method and an arc-shaped bifurcated thin-walled vacuum chamber. BACKGROUND

[0002] In a synchrotron device, a vacuum chamber provides a necessary vacuum environment for the stable operation of a beam. In order to reduce the influence of eddy current on the stability of the beam, a stainless steel thin-walled tube with a thickness in the range of 0.1mm to 0.5mm is usually used, and a reinforcing rib is welded outside the tube to make a thin-walled vacuum chamber with an arc-shaped bifurcated structure.

[0003] For a thin-walled vacuum chamber with a larger cross-sectional size, after processing, it should not only have sufficient structural strength and rigidity to withstand atmospheric pressure difference, but also meet strict geometric tolerance requirements such as angle, radius, length and flatness. In addition, the thin-walled vacuum chamber must not have structural defects such as buckling and wrinkling during the manufacturing process to ensure its final performance and reliability.

[0004] However, in the current actual production, there are many problems in processing such thin-walled vacuum chambers using traditional processes. For example, when the stainless steel thin-walled tube and the reinforcing rib are directly vacuum welded after being positioned by a fixed mold, serious deformation of the thin-walled tube, welding leakage and insufficient overall structural strength often occur. These problems result in low product qualification rate, high manufacturing cost, and seriously affect the batch production and engineering application of the thin-walled vacuum chamber. SUMMARY

[0005] The present application provides a thin-walled vacuum chamber processing method and an arc-shaped bifurcated thin-walled vacuum chamber to solve the problems of low qualification rate, high manufacturing cost and long processing cycle caused by large deformation and leakage in the manufacture of thin-walled reinforced vacuum chambers using traditional technology, and to improve manufacturing precision, structural reliability and production efficiency, and reduce manufacturing cost.

[0006] The present application provides a thin-walled vacuum chamber processing method, comprising: processing a thin-walled tube; fixing the thin-walled tube with a mold; first performing air burning treatment on the thin-walled tube, and then placing it in a vacuum brazing furnace for vacuum brazing; and assembling the thin-walled tube with an ultrahigh vacuum flange.

[0007] According to one embodiment of the present application, the step of processing the thin-walled tube further comprises a titanium alloy plate pretreatment step, specifically comprising: annealing heat treatment of the titanium alloy plate; opening the titanium alloy plate and cutting it to the required size, wherein the size tolerance of the cut titanium alloy plate is controlled within ±0.05mm, and a 1-2mm allowance is left in the length direction of the titanium alloy plate.

[0008] According to one embodiment of the present application, the step of processing the thin-walled tube includes ultrasonic cleaning of the cut titanium alloy plate, resistance welding fixation of the thin-walled tube, installation of inner and outer fixtures of the thin-walled tube after resistance welding, laser welding of the thin-walled tube, and vacuum leak detection after welding.

[0009] According to one embodiment of the present application, the step of fixing the thin-walled tube and the mold includes sequentially placing the reinforcing ribs after cutting and polishing according to the positions of the reinforcing rib installation grooves in the brazing mold assembly, placing the thin-walled tube after vacuum leak detection into the brazing mold assembly and making the reinforcing ribs in close contact with the thin-walled tube, and closing and fixing the brazing mold assembly.

[0010] According to one embodiment of the present application, the brazing mold assembly includes a first brazing mold having a first mold space in which a reinforcing rib installation groove is arranged and around which a boss is arranged, the boss being provided with a wedge-shaped positioning block, a second brazing mold having a second mold space opposite to the first mold space and around which a groove corresponding to the boss is arranged, the groove being provided with a wedge-shaped positioning groove corresponding to the wedge-shaped positioning block, the first mold space and the second mold space being used to accommodate a thin-walled vacuum chamber composed of the thin-walled tube and the reinforcing rib, and a fastening screw used to fix the first brazing mold and the second brazing mold, the first brazing mold and the second brazing mold being made of Al2O3.

[0011] According to one embodiment of the present application, the step of air-burning the thin-walled tube includes placing the thin-walled tube and the mold into a vacuum brazing furnace for super-flatness with a height gauge after fixing the thin-walled tube and the mold, heating the vacuum brazing furnace to 900-1000°C, heating and cooling in three stages within three hours, starting to cool with the furnace to normal temperature after reaching the required temperature, and checking whether the positions of the thin-walled tube and the reinforcing rib change and performing vacuum leak detection.

[0012] According to one embodiment of the present application, the step of placing into a vacuum brazing furnace for vacuum brazing includes soldering at the contact position of the thin-walled tube and the reinforcing rib, placing the thin-walled tube and the reinforcing rib into the vacuum brazing furnace with the mold, super-flatly brazing the mold with the height gauge after placing the thin-walled tube and the reinforcing rib into the vacuum brazing furnace, heating the vacuum brazing furnace to 1050-1085°C, heating and cooling in three stages, taking out after the temperature drops to normal temperature, and completing processing.

[0013] The application further provides an arc-shaped bifurcated thin-wall vacuum chamber, which is formed by the thin-wall vacuum chamber processing method in the above embodiment; the arc-shaped bifurcated thin-wall vacuum chamber comprises a vacuum chamber main body, which is arc-shaped as a whole, and two ends of the vacuum chamber main body are respectively provided with ultrahigh vacuum flanges; the vacuum chamber main body comprises a first vacuum chamber, which constitutes a part of the vacuum chamber main body in the length direction, the first end of the first vacuum chamber is used as one end of the vacuum chamber main body, and one of the ultrahigh vacuum flanges is arranged at the first end; a second vacuum chamber and a third vacuum chamber are respectively connected to the end of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber jointly constitute the remaining part of the vacuum chamber main body in the length direction, and the other ultrahigh vacuum flange is arranged at the end of the second vacuum chamber and the third vacuum chamber.

[0014] According to one embodiment of the application, the cross sections of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber are all rectangular; the cross sections of the first vacuum chamber and the third vacuum chamber are consistent along the length direction; the cross section of the second vacuum chamber is trumpet-shaped along the length direction, and the cross section becomes larger from the side close to the first vacuum chamber to the side far from the first vacuum chamber; the height of the first vacuum chamber is consistent with the height of the second vacuum chamber, and the height of the third vacuum chamber is smaller than the height of the first vacuum chamber.

[0015] According to one embodiment of the application, the first vacuum chamber, the second vacuum chamber and the third vacuum chamber are respectively provided with a reinforcing rib structure, wherein: the second vacuum chamber comprises a second thin-wall tube, one side of the second thin-wall tube towards the third vacuum chamber is a second tube side plate without the reinforcing rib structure, and the other three surfaces of the second thin-wall tube are provided with at least one second longitudinal reinforcing rib extending along the length direction of the second vacuum chamber and a plurality of second transverse reinforcing ribs perpendicular to the second longitudinal reinforcing rib; the third vacuum chamber comprises a third thin-wall tube, one side of the third thin-wall tube towards the second vacuum chamber is a third tube side plate without the reinforcing rib structure, and the other three surfaces of the third thin-wall tube are provided with at least one third longitudinal reinforcing rib extending along the length direction of the third vacuum chamber and a plurality of third transverse reinforcing ribs perpendicular to the third longitudinal reinforcing rib; and the second tube side plate and the third tube side plate form an equidistant structural gap.

[0016] The thin-wall vacuum chamber processing method and the arc-shaped bifurcated thin-wall vacuum chamber provided by the present application effectively reduce the longitudinal deformation and leakage risk of the thin-wall tube caused by thermal stress in the welding process through the process improvement of first air-burning treatment on the thin-wall tube and then vacuum brazing, and improve the product qualification rate and structural stability. The arc-shaped bifurcated thin-wall vacuum chamber manufactured by the thin-wall vacuum chamber processing method not only ensures the sealing performance and mechanical strength of the arc-shaped bifurcated thin-wall vacuum chamber under complex working conditions, but also significantly improves the production efficiency and product utilization rate, reduces the processing cycle and manufacturing cost. Meanwhile, the method combines the mold fixing and ultrahigh vacuum flange assembly welding process, and further enhances the overall performance of the thin-wall vacuum chamber.

[0017] In addition, the arc-shaped bifurcated thin-wall vacuum chamber structure provided by the present application integrates the functions originally realized by the cutting magnet vacuum chamber and the dipole magnet vacuum chamber into one, forms a bifurcated design including a first vacuum chamber, a second vacuum chamber and a third vacuum chamber, not only meets the spatial layout requirement of the beam extraction system, but also is beneficial to the miniaturization development of the synchrotron device. This structure simplifies the assembly process, reduces the number of vacuum cavities, thereby effectively reducing the equipment manufacturing and maintenance cost, and further guarantees the reliability of the structure and the feasibility of the engineering application due to the adoption of the above-mentioned thin-wall vacuum chamber processing method. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is a flowchart of the thin-wall vacuum chamber processing method provided by the present application.

[0020] Figure 2 is a structure diagram of a brazing mold assembly used in the thin-wall vacuum chamber processing method of the present application.

[0021] Figure 3 is a structure diagram of a first brazing mold of the brazing mold assembly of the present application.

[0022] Figure 4 is a structure diagram of a second brazing mold of the brazing mold assembly of the present application.

[0023] Figure 5 is a structure diagram of the arc-shaped bifurcated thin-wall vacuum chamber provided by the present application.

[0024] Figure 6It is a partial enlarged structure schematic view of the second vacuum chamber and the third vacuum chamber of the arc-shaped bifurcated thin-wall vacuum chamber.

[0025] Reference signs:

[0026] 100, thin-wall vacuum chamber; 200, first brazing mold; 300, second brazing mold; 202, boss; 204, wedge-shaped positioning block; 206, reinforcing rib mounting groove; 208, fastening screw; 302, groove; 304, wedge-shaped positioning groove; 400, first vacuum chamber; 500, second vacuum chamber; 600, third vacuum chamber; 700, ultrahigh vacuum flange; 502, second thin-wall tube; 504, second transverse reinforcing rib; 506, second longitudinal reinforcing rib; 508, second tube side plate; 602, third thin-wall tube; 604, third transverse reinforcing rib; 606, third longitudinal reinforcing rib; 608, third tube side plate. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described below in conjunction with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0028] In the description of the embodiments of the present application, it should be noted that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms “first”, “second”, “third” are only for the purpose of description, and cannot be understood as indicating or implying relative importance. It should also be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms “arrange”, “mount”, “connect” should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0029] The specific embodiments of the thin-wall vacuum chamber processing method and the arc-shaped bifurcated thin-wall vacuum chamber of the present application will be described below in conjunction with the drawings. Figures 1-6 The specific embodiments of the thin-wall vacuum chamber processing method and the arc-shaped bifurcated thin-wall vacuum chamber of the present application will be described below in conjunction with the drawings.

[0030] The present application provides a thin-wall vacuum chamber processing method, which comprises the following steps:

[0031] Step 110, processing the thin-walled tube. The thin-walled tube is precisely formed by die pressing or roll bending to preliminarily form the required arc shape and bifurcated structure, and is subjected to surface cleaning and oil removal treatment, etc. The material of the thin-walled tube is preferably TC4, and the thickness is 0.1-0.2 mm. The thin-walled tube uses titanium alloy TC4 material with higher strength limit and lighter weight, which improves the structural strength of the large-section arc-shaped bifurcated thin-walled vacuum chamber, and meets the requirements of high stability and high reliability of the small-sized medical synchrotron.

[0032] Step 120, fixing the thin-walled tube and the mold. The processed thin-walled tube is firmly connected with the mold to ensure that no displacement or deformation occurs during subsequent heat treatment and welding. The mold is designed to match the shape of the thin-walled tube, which can effectively control the distribution of thermal stress and prevent local collapse or wrinkling, thereby improving the dimensional accuracy and consistency of the overall structure.

[0033] Step 130, first performing air-burning treatment on the thin-walled tube, and then placing it in a vacuum brazing furnace for vacuum brazing. The thin-walled tube fixed with the mold is placed in a heating device for preheating and holding treatment (i.e. air-burning) in a solder-free state to remove residual gases, moisture and organic matter, and release the residual stress inside the material. Subsequently, the assembly is transferred to a vacuum brazing furnace, where high-strength and high-sealing connections between components are achieved using solder in a high-temperature vacuum environment. This process significantly reduces deformation and weld leakage problems caused by thermal stress concentration, improving product yield and structural reliability.

[0034] Step 140, assembling and welding the thin-walled tube and the ultra-high vacuum flange. After completing the vacuum brazing and cooling, the thin-walled vacuum chamber body and the standard specification ultra-high vacuum flange are assembled and welded. Preferably, the flange and the end of the thin-walled tube are finely machined before welding to ensure close fitting of the mating surfaces; high-energy beam welding techniques such as electron beam welding or laser welding can be used during the welding process to achieve deep penetration, low heat-affected zone and high-quality welding, thereby ensuring the air tightness and mechanical strength of the overall structure and meeting the technical requirements of the ultra-high vacuum environment in the synchrotron system.

[0035] Further, according to the thin-walled vacuum chamber processing method of the present application, before the step of processing the thin-walled tube, a titanium alloy plate pretreatment step is further included, which specifically comprises:

[0036] Step 101, annealing heat treatment of the titanium alloy plate. The titanium alloy plate is subjected to homogenizing annealing treatment before processing to eliminate residual stress generated during rolling, improve its plasticity and processability, and improve the dimensional stability during subsequent forming.

[0037] Step 102, open flat the titanium alloy plate and cut to the required size, wherein the titanium alloy sheet is ensured to be flat when opened by the opening machine, the size tolerance of the cut titanium alloy plate is controlled within ±0.05mm, and a 1-2mm allowance is left in the length direction of the titanium alloy plate. High-precision opening equipment is used to flatten the annealed titanium alloy plate to remove slight bending or wavy deformation of the plate during transportation or storage. Then, laser cutting or precision shearing equipment is used to accurately cut the required shape and size of the blank according to the design drawing, preferably strictly controlling the cutting tolerance within ±0.05mm to ensure the consistency and precision of subsequent forming processing. A 1-2mm allowance can be reserved in the length direction to compensate for possible shrinkage or misplacement during subsequent processing, thereby ensuring the geometric precision and assembly requirements of the final product.

[0038] Further, according to the thin-walled vacuum chamber processing method of the present application, the step of processing the thin-walled tube includes:

[0039] Step 111, ultrasonic cleaning of the cut titanium alloy plate. Before the titanium alloy plate is processed into a thin-walled tube, a multi-pass ultrasonic cleaning process is used to remove oil stains, metal debris and other micron-level contaminants from the surface of the plate, ensuring that the material surface cleanliness meets the use requirements in a high vacuum environment, thereby improving the subsequent welding quality and structural reliability.

[0040] Step 112, resistance welding of the thin-walled tube. The cleaned titanium alloy plate is rolled into a thin-walled tubular structure of the required shape, and resistance welding is used for preliminary positioning welding at the joint to achieve stable connection and prevent misalignment or collapse during subsequent laser welding, ensuring the continuity and consistency of the welding path.

[0041] Step 113, installation of the thin-walled tube inner and outer tooling after resistance welding. After completing the resistance welding, a detachable support tooling can be installed inside the thin-walled tube, and a limiting and pressing device is provided outside the mold to ensure that the thin-walled tube maintains a stable geometric shape during subsequent laser welding, avoiding local collapse, wrinkles or size deviation caused by thermal deformation.

[0042] Step 114, laser welding of the thin-walled tube. High-energy density and deep penetration laser welding technology is used to perform high-quality sealed welding of the thin-walled tube joint along the preset trajectory, and the welding process is precisely controlled by automatic equipment to ensure uniform and defect-free welds, while minimizing the heat-affected zone, reducing the risk of welding deformation, and improving the mechanical strength and air tightness of the welded joint.

[0043] Step 115, vacuum leak detection after welding, preferably with a leakage rate ≤1×10 -8 Pa·l / s·cm2 After the thin-walled tube is welded, it is placed in a special vacuum detection system for overall air tightness test. High-precision detection equipment such as a helium mass spectrometer is used to scan the weld and the connecting part point by point, so as to ensure that the thin-walled tube has extremely low leakage rate in an ultra-high vacuum environment and meets the strict requirements of the synchrotron system on the air tightness of the vacuum chamber.

[0044] Further, according to the thin-walled vacuum chamber processing method, the step of fixing the thin-walled tube and the mold comprises:

[0045] Step 121, the reinforcing ribs after cutting and polishing are placed in position according to the position of the reinforcing rib mounting groove in the brazing mold assembly. The reinforcing ribs that have been accurately cut according to the design size and have been surface polished are positioned and assembled, and are accurately embedded into the reinforcing rib mounting groove in the brazing mold assembly according to the predetermined spacing and direction, so as to ensure that the reinforcing ribs and the mold are tightly matched and accurately positioned, and to provide a basis for stable connection with the thin-walled tube.

[0046] Step 122, the thin-walled tube after vacuum leak detection is placed in the brazing mold assembly, and the reinforcing ribs are in close contact with the thin-walled tube. The thin-walled tube that has completed laser welding and passed vacuum leak detection is stably placed in the brazing mold assembly provided with reinforcing ribs, the thin-walled tube is guided by the mold structure to uniformly adhere to the pre-installed reinforcing ribs, and no gap is ensured between the two, so as to improve the reliability and thermal conduction consistency of the structure connection in the subsequent vacuum brazing process.

[0047] Step 123, the brazing mold assembly is closed and fixed. The upper and lower molds can be closed and locked by hydraulic or mechanical means, so that the entire thin-walled tube and reinforcing rib assembly maintain stable three-dimensional spatial position in the mold, prevent displacement, deformation or separation due to external force or thermal stress during subsequent air burning and vacuum brazing, and ensure that the geometric accuracy and overall strength of the final formed structure meet the design requirements.

[0048] As Figure 2 , Figure 3 and Figure 4As shown, the above brazing die assembly preferably comprises: a first brazing die 200 having a first die space, a reinforcing rib mounting groove 206 is arranged in the first die space, a boss 202 is arranged around the first die space, and a wedge-shaped positioning block 204 is arranged on the boss 202; a second brazing die 300 having a second die space opposite to the first die space, a groove 302 corresponding to the boss 202 is arranged around the second die space, and a wedge-shaped positioning groove 304 corresponding to the wedge-shaped positioning block 204 is arranged in the groove 302, the first die space and the second die space are used to accommodate the thin-walled vacuum chamber 100 composed of the thin-walled tube and the reinforcing rib; a fastening screw 208 is used to mount and fix the first brazing die 200 and the second brazing die 300; and the materials of the first brazing die 200 and the second brazing die 300 are Al2O3. In order to show the state of the thin-walled vacuum chamber 100 in the first die space and the second die space, the figure of the second brazing die 300 in the above description is cut. Compared with the conventional method, the brazing die assembly combines the process flow of pre-emptying and then brazing, significantly reduces the risk of longitudinal deformation and weld leakage of the thin-walled tube caused by thermal stress concentration, improves the qualification rate and structural reliability of the product, and is especially suitable for manufacturing arc bifurcated thin-walled vacuum chambers 100 with large cross sections and high precision requirements. Figure 2

[0049] According to the brazing die assembly, specifically, the first brazing die 200 and the second brazing die 300 are respectively provided with the first die space and the second die space corresponding to each other, which are used to accommodate the vacuum chamber structure assembled by the thin-walled tube and the reinforcing rib. The first brazing die 200 is provided with the reinforcing rib mounting groove 206 for accurately positioning and fixing the position of the reinforcing rib, and the boss 202 is arranged around the first brazing die 200, and the wedge-shaped positioning block 204 is arranged on the boss 202. The second brazing die 300 is provided with the groove 302 matched therewith and the wedge-shaped positioning groove 304 located in the groove 302. The first die and the second die are high-precision aligned through the cooperation of the wedge-shaped positioning block 204 and the wedge-shaped positioning groove 304, which ensures the equidistant distribution of the reinforcing rib on the thin-walled tube, and the cooperation of the boss 202 and the groove 302 also guarantees the close contact of the upper and lower surfaces of the thin-walled tube and the reinforcing rib, thereby improving the overall structural consistency.

[0050] Further, the first brazing die 200 and the second brazing die 300 are preferably made of Al2O3 ceramic material, which has the characteristics of low thermal expansion coefficient, high temperature resistance, and good chemical stability, can effectively reduce the thermal deformation of the die along the longitudinal direction during heating, thereby improving the dimensional accuracy and form tolerance control (which can be stably maintained within ±0.05 mm) of the thin-walled vacuum chamber 100 after forming. The dies are preferably locked and fixed by the fastening screw 208, which ensures that the entire assembly structure remains stable and does not deform during the subsequent emptying and vacuum brazing process.

[0051] ​Further, according to the thin-walled vacuum chamber processing method, the air-burning treatment step of the thin-walled tube comprises the following steps:

[0052] In step 131, after the thin-walled tube and the mold are fixed, the whole is placed in a vacuum brazing furnace for leveling. Specifically, before the brazing mold assembly with the thin-walled tube and the reinforcing rib is placed in the vacuum brazing furnace, the mold assembly is calibrated horizontally using a high-precision height gauge to ensure that it is in a completely horizontal state in the furnace, avoiding local collapse or deformation of the thin-walled tube due to gravity or uneven thermal stress during heating, thereby ensuring the uniformity and stability of the subsequent air-burning and brazing processes.

[0053] In step 132, the vacuum brazing furnace is heated to 900-1000℃. The vacuum brazing furnace is started and gradually heated to a set temperature range of 900-1000℃. This temperature range can effectively remove residual gases, moisture and organic pollutants on the surface of the thin-walled tube and the mold assembly, and also helps to release residual stress in the material, providing good metallurgical bonding conditions for the subsequent brazing process.

[0054] In step 133, the temperature is raised and lowered in three stages within three hours. Specifically, the segmented temperature control strategy is adopted in the whole air-burning process. First, the temperature is raised from room temperature to 600℃ at a slow rate (such as 100℃ / h) for the first stage of heat preservation. Then, the temperature is continuously raised to the target temperature of 900-1000℃ at the same or slightly higher rate to complete the second stage of heating. Finally, the temperature is gradually lowered after reaching the set temperature to about 600℃ in the third stage of slow cooling to control the change of thermal stress and prevent deformation or cracking of the thin-walled structure due to rapid cooling and heating.

[0055] In step 134, after the required temperature is reached, the furnace is cooled to room temperature. After the high-temperature air-burning is completed and the temperature is lowered to 600℃, the heating system is turned off and the mold assembly is naturally cooled to room temperature with the furnace body. The whole cooling process lasts for several hours to minimize the impact of thermal shock on the titanium alloy thin-walled structure and ensure the integrity and dimensional stability of the connection interface between the thin-walled tube and the reinforcing rib.

[0056] In step 135, the position of the thin-walled tube and the reinforcing rib is checked for changes, and vacuum leak detection is performed. After the mold assembly is completely cooled, it is taken out, and the relative position of the thin-walled tube and the reinforcing rib is reviewed using high-precision measuring tools to confirm that there is no significant displacement or deformation. Then, the overall structure is tested again for vacuum leak detection to detect whether there is a micro-leak to ensure that its air tightness meets the requirements of the ultra-high vacuum environment, laying a good foundation for the subsequent vacuum brazing process.

[0057] Further, according to the thin-walled vacuum chamber processing method, the air-burning treatment step of the thin-walled tube comprises the following steps:

[0058] Step 136, welding at the contact position of the thin-walled tube and the reinforcing rib. Specifically, the welding process preferably uses a welding machine to complete the HJNi-T7 solder coating, and the solder at the contact position of the reinforcing rib and the thin-walled tube must be uniform, and the solder diameter is preferably about 3 mm. The distribution position and amount of solder are precisely controlled by automatic equipment to ensure that the solder can fully fill the joint gap during welding, thereby improving the welding strength and sealing performance.

[0059] Step 137, after the thin-walled tube and the reinforcing rib are placed in the vacuum brazing furnace with the mold, the mold is leveled with a height gauge. Specifically, after the entire assembly of the thin-walled tube, the reinforcing rib, and the mold is placed in the vacuum brazing furnace, the mold is leveled with a high-precision height gauge to ensure that it is in the ideal horizontal state in the furnace, thereby avoiding uneven solder flow or structural deformation due to inclination or uneven local heating, and ensuring that the components are evenly heated during brazing and the welding quality is stable and reliable.

[0060] Step 138, the temperature of the vacuum brazing furnace is raised to 1050-1085°C. Start the vacuum brazing furnace and gradually raise the furnace temperature to the temperature range of 1050-1085°C according to the set program. This temperature range can make the HJNi-T7 solder fully melt and wet the surface of the base material, achieving firm metallurgical bonding between the thin-walled tube and the reinforcing rib. At the same time, the vacuum degree in the furnace is maintained to prevent oxidation and impurity contamination, ensuring that the weld structure is dense and the air tightness is excellent.

[0061] Step 139, the temperature is raised and lowered in three stages, and the product is taken out after the temperature drops to room temperature. Specifically, the entire brazing process uses a three-stage temperature control strategy: the first stage is slow heating (e.g., from room temperature to 600°C) to remove residual gas; the second stage is rapid heating to the brazing temperature (1050-1085°C) and holding for a certain time to promote the flow of solder and complete the welding; the third stage is gradient cooling, first slow cooling to below 600°C and then cooling to room temperature with the furnace to reduce the effect of thermal stress and prevent deformation or cracking of the thin-walled structure. After cooling is completed, the mold assembly is taken out, the vacuum brazing process is completed, and a complete and dimensionally stable arc-shaped bifurcated thin-walled vacuum chamber semi-finished product is obtained, which is ready for subsequent assembly with the ultra-high vacuum flange.

[0062] As Figure 1The flowchart of the thin-wall vacuum chamber processing method of the preferred embodiment of the present application is shown, and the specific processing steps are as follows: first, annealing heat treatment is performed on the ultra-thin titanium alloy plate to eliminate internal residual stress and improve plasticity and processability. Subsequently, the titanium alloy plate is opened and flattened by high-precision opening and flattening equipment, and the required size and shape of the blank is accurately cut by laser cutting technology, ensuring that the size tolerance is within ±0.05mm. Then, the thin-wall tube processing is performed, the cut titanium alloy plate is ultrasonically cleaned to remove surface contaminants, and then it is rolled into a thin-wall tubular structure and the initial joint is fixed by resistance welding. After that, the stiffeners are cut and polished, and embedded into the brazing mold assembly according to the predetermined position. After the thin-wall tube is in close contact with the stiffeners, the brazing mold assembly is closed and fixed using hydraulic or mechanical methods to ensure that the components remain stable during the subsequent process, achieving the fixation of the thin-wall tube inner and outer molds and the overall brazing mold. Next, the assembled components are subjected to an ultra-thin-wall vacuum chamber air firing process to remove residual gases and organic matter and release internal stress. After the air firing is completed, HJNi-T7 solder is evenly applied at the contact position of the thin-wall tube and the stiffener, and then the assembly is placed in a vacuum brazing furnace for high-temperature vacuum brazing to ensure high strength and high sealing performance of the weld. Finally, the brazed thin-wall vacuum chamber is assembled with a standard specification ultra-high vacuum flange, and high-energy beam welding technology such as electron beam welding or laser welding is used to achieve deep penetration, low heat-affected zone and high-quality welding, thereby ensuring the air tightness and mechanical strength of the overall structure and meeting the technical requirements of the ultra-high vacuum environment in the synchrotron system.

[0063] Currently, in the beam extraction system of a synchrotron, three arc-shaped cut magnets and one extraction dipole magnet are usually required to extract higher energy beams, and the magnets need to have larger wire specifications and thicker shielding layers. The corresponding arc-shaped vacuum cavities are long in length, resulting in poor structural stability and high installation difficulty. At the same time, the cut magnets occupy a large amount of longitudinal space, limiting the shortening of the circumference of the synchrotron, which is not conducive to the popularization and application of small-sized accelerators. Therefore, in order to make the vacuum cavity in the beam extraction system meet the requirements of the new generation of small-sized accelerators, and considering the characteristics of the cut magnet vacuum chamber and the dipole magnet vacuum chamber, it is particularly important to propose an arc-shaped vacuum cavity based on the beam extraction system.

[0064] Therefore, the present application also provides an arc-shaped bifurcated thin-wall vacuum chamber, which is processed by the thin-wall vacuum chamber processing method of the above-mentioned embodiment. The arc-shaped bifurcated thin-wall vacuum chamber provided by the present application is described below, and the arc-shaped bifurcated thin-wall vacuum chamber described below can be correspondingly referred to the thin-wall vacuum chamber processing method described above.

[0065] As Figure 5 and Figure 6As shown, the arc-shaped bifurcated thin-walled vacuum chamber 100 includes a vacuum chamber body, which is arc-shaped as a whole, and two ultra-high vacuum flanges 700 are arranged at two ends of the vacuum chamber body. The vacuum chamber body includes a first vacuum chamber 400, which constitutes a part of the length direction of the vacuum chamber body, and a first end of the first vacuum chamber 400 is arranged with one of the ultra-high vacuum flanges 700 as one end of the vacuum chamber body; a second vacuum chamber 500 and a third vacuum chamber 600 are connected to the end of the first vacuum chamber 400, and the second vacuum chamber 500 and the third vacuum chamber 600 jointly constitute the remaining part of the length direction of the vacuum chamber body, and the ends of the second vacuum chamber 500 and the third vacuum chamber 600 are jointly arranged with the other ultra-high vacuum flange 700. Specifically, the arc-shaped bifurcated structure integrates the functions that need to be realized by the cutting magnet vacuum chamber and the dipole magnet vacuum chamber in the conventional beam extraction system into one, forming an integrated compact vacuum cavity, effectively reducing the longitudinal space occupation, and being conducive to the miniaturization design and engineering application popularization of the synchrotron.

[0066] Preferably, the thickness of the thin-walled tube in the arc-shaped bifurcated thin-walled vacuum chamber 100 is preferably 0.1-0.2mm, which significantly reduces the eddy current heating effect generated in the process of rapid change of the magnetic field, and improves the stability and energy efficiency of the system. At the same time, the thin-walled tube adopts titanium alloy TC4 material with higher strength limit and lighter weight, which not only meets the strength requirements of the large-section arc-shaped structure, but also meets the use requirements of the miniaturized synchrotron on high stability and high reliability. In addition, the ultra-high vacuum flange 700 at both ends of the vacuum chamber is preferably a titanium alloy flange (material TC4), which has good material compatibility with the thin-walled tube body, ensures the sealing performance and mechanical strength of the entire vacuum chamber in the ultra-high vacuum environment, and further improves the comprehensive performance and engineering practicability of the product.

[0067] Further, according to the arc-shaped bifurcated thin-walled vacuum chamber 100 of the present application, the cross sections of the first vacuum chamber 400, the second vacuum chamber 500 and the third vacuum chamber 600 are all rectangular, which not only facilitates manufacturing and processing, but also ensures good structural strength and stability of each part when subjected to atmospheric pressure difference.

[0068] The cross sections of the first vacuum chamber 400 and the third vacuum chamber 600 along the length direction are consistent, and the internal space size of these two parts is constant, which is conducive to simplifying the design and ensuring the stability and consistency when the beam passes through. Such consistency helps to control the uniformity of the magnetic field on the beam path and reduce unnecessary fluctuations or interference.

[0069] The cross section of the second vacuum chamber 500 is trumpet-shaped along the length direction, gradually increasing from near the first vacuum chamber 400 to far from the first vacuum chamber 400. This gradual design can effectively guide the beam to smoothly transition from the main channel to the branch channel, avoiding beam scattering or energy loss caused by sudden changes, while also helping to optimize the magnetic field distribution and improve the extraction efficiency.

[0070] The heights of the first vacuum chamber 400 and the second vacuum chamber 500 are consistent, which ensures that the beam does not produce unnecessary deviation or distortion when entering the curved arc segment from the straight segment due to height differences. The height of the third vacuum chamber 600 is smaller than that of the first vacuum chamber 400. This design can further reduce the overall size and weight of the device while meeting the beam transmission requirements, which is beneficial to the miniaturization and lightweight of the synchrotron. In addition, the design of different heights can better adapt to the energy requirements and physical properties of the beam in different regions, improving the flexibility and adaptability of the entire system.

[0071] Further, according to the arc-shaped bifurcated thin-walled vacuum chamber 100 of the present application, the first vacuum chamber 400, the second vacuum chamber 500 and the third vacuum chamber 600 are respectively provided with a reinforcing rib structure. The second vacuum chamber 500 includes a second thin-walled tube 502, one side of the second thin-walled tube 502 facing the third vacuum chamber 600 is a second tube side plate 508 without a reinforcing rib structure, and the other three surfaces of the second thin-walled tube 502 are provided with at least one second longitudinal reinforcing rib 506 extending along the length direction of the second vacuum chamber 500, and a plurality of second transverse reinforcing ribs 504 perpendicular to the second longitudinal reinforcing rib 506. The third vacuum chamber 600 includes a third thin-walled tube 602, one side of the third thin-walled tube 602 facing the second vacuum chamber 500 is a third tube side plate 608 without a reinforcing rib structure, and the other three surfaces of the third thin-walled tube 602 are provided with at least one third longitudinal reinforcing rib 606 extending along the length direction of the third vacuum chamber 600, and a plurality of third transverse reinforcing ribs 604 perpendicular to the third longitudinal reinforcing rib 606. The second tube side plate 508 and the third tube side plate 608 form an equidistant structural gap. This reinforcing rib arrangement takes into account the functional design of the local area while ensuring the overall structural strength of the vacuum chamber. By arranging longitudinal and transverse reinforcing rib structures on the other three surfaces of the second vacuum chamber 500 and the third vacuum chamber 600 except the abutting surface, the bending and torsional resistance of each vacuum chamber when subjected to external atmospheric pressure is effectively improved, preventing buckling or deformation caused by local stress concentration.

[0072] Preferably, no reinforcing rib structure is arranged on the second tube side plate 508 and the third tube side plate 608 to ensure that the interface between the two is smooth and flat, facilitating subsequent assembly, while avoiding the problems of weld interference and stress concentration. In addition, due to the space limitation between the second tube side plate 508 and the third tube side plate 608, no reinforcing rib structure is arranged, and the thickness of the side plate of the second tube side plate 508 and the third tube side plate 608 is preferably greater than the thickness of the remaining thin-walled tube part, which can be controlled in the range of 0.5-1mm, which not only meets the beam envelope requirement, but also does not affect the lightweight design of the overall structure due to excessive thickness. The structural gap formed between the second tube side plate 508 and the third tube side plate 608 is preferably kept at an equal interval of 6-7mm. This structural optimization makes the arc-shaped bifurcated thin-walled vacuum chamber 100 have higher mechanical stability and electromagnetic compatibility while realizing functional integration, and is particularly suitable for beam extraction system applications in high-precision and miniaturized synchrotrons.

[0073] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "aspects", "specific aspects", or "some aspects" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or aspect are included in at least one embodiment or aspect of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or aspect. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or aspects. In addition, different embodiments or aspects described in the present specification and the features of different embodiments or aspects can be combined and combined by those skilled in the art without contradiction.

[0074] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An arc-shaped bifurcated thin-walled vacuum chamber, characterized in that, the arc-shaped bifurcated thin-walled vacuum chamber comprises a vacuum chamber body which is arc-shaped as a whole, and two ultra-high vacuum flanges are arranged at two ends of the vacuum chamber body respectively; the vacuum chamber body comprises: a first vacuum chamber which constitutes a part of the vacuum chamber body in the length direction, and a first end of the first vacuum chamber is arranged as one of the two ends of the vacuum chamber body and is provided with one of the two ultra-high vacuum flanges; a second vacuum chamber and a third vacuum chamber which are connected to the ends of the first vacuum chamber respectively, and the second vacuum chamber and the third vacuum chamber jointly constitute the remaining part of the vacuum chamber body in the length direction, and the ends of the second vacuum chamber and the third vacuum chamber are jointly provided with the other ultra-high vacuum flange; the cross sections of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber are all rectangular; the cross sections of the first vacuum chamber and the third vacuum chamber are consistent along the length direction; the cross section of the second vacuum chamber is trumpet-shaped along the length direction, and the cross section becomes larger from the side close to the first vacuum chamber to the side far from the first vacuum chamber; the heights of the first vacuum chamber and the second vacuum chamber are consistent, and the height of the third vacuum chamber is smaller than the height of the first vacuum chamber; the arc-shaped bifurcated thin-walled vacuum chamber is processed by the following thin-walled vacuum chamber processing method: processing the thin-walled tube; fixing the thin-walled tube and the mold; firstly, performing air burning treatment on the thin-walled tube, and then performing vacuum brazing on the thin-walled tube in a vacuum brazing furnace; assembling the thin-walled tube and the ultra-high vacuum flange.

2. The arcuate bifurcated thin-walled vacuum chamber of claim 1, wherein, Before the step of processing the thin-walled tube, the titanium alloy plate pretreatment step is further included, specifically comprising: annealing heat treatment is performed on the titanium alloy plate; the titanium alloy plate is opened and cut to the required size, wherein the size tolerance of cutting the titanium alloy plate is controlled within ±0.05mm, and a 1-2mm allowance is left in the length direction of the titanium alloy plate.

3. The arcuate bifurcated thin-walled vacuum chamber of claim 2, wherein, The step of processing the thin-walled tube comprises: ultrasonic cleaning is performed on the cut titanium alloy plate; resistance welding is performed on the thin-walled tube first; after resistance welding, the inner and outer tooling of the thin-walled tube are installed in place; welding of the thin-walled tube is completed by laser welding; vacuum leak detection is performed after welding.

4. The arcuate bifurcated thin-walled vacuum chamber according to any one of claims 1 to 3, wherein, The step of fixing the thin-walled tube and the mold comprises: the reinforcing ribs after cutting and polishing are placed in place according to the positions of the reinforcing rib mounting grooves in the brazing mold assembly; the thin-walled tube after vacuum leak detection is placed in the brazing mold assembly, and the reinforcing ribs are in close contact with the thin-walled tube; the brazing mold assembly is closed and fixed.

5. The arcuate bifurcated thin-walled vacuum chamber of claim 4, wherein, The brazing mold assembly comprises: a first brazing mold having a first mold space, a reinforcing rib mounting groove is arranged in the first mold space, a boss is arranged around the first mold space, and a wedge-shaped positioning block is arranged on the boss; A second brazing die having a second die space opposite to the first die space, a groove corresponding to the boss is arranged around the second die space, a wedge-shaped positioning groove corresponding to the wedge-shaped positioning block is arranged in the groove, and the first die space and the second die space are used to accommodate the thin-walled vacuum chamber composed of the thin-walled tube and the reinforcing rib; A fastening screw is used to fix the first brazing die and the second brazing die; The materials of the first brazing die and the second brazing die are Al2O3.

6. The arcuate bifurcated thin-walled vacuum chamber of claim 4, wherein, The step of air-burning the thin-walled tube includes: After the thin-walled tube is fixed with the die, the whole is put into a vacuum brazing furnace and is leveled by a height ruler; The vacuum brazing furnace is heated to 900-1000℃; The heating and cooling are carried out in three stages within three hours; After the required temperature is reached, the furnace cooling is started to normal temperature; Whether the positions of the thin-walled tube and the reinforcing rib change is checked, and vacuum leak detection is carried out.

7. The arcuate bifurcated thin-walled vacuum chamber of claim 6, wherein, The step of putting into the vacuum brazing furnace for vacuum brazing includes: The solder is struck at the contact position of the thin-walled tube and the reinforcing rib; After the thin-walled tube and the reinforcing rib are put into the vacuum brazing furnace with the die, the height ruler is used to level the brazing die; The vacuum brazing furnace is heated to 1050-1085℃; The heating and cooling are carried out in three stages, and after the temperature is reduced to normal temperature, the processing is completed.

8. The arcuate bifurcated thin-walled vacuum chamber of claim 1, wherein, The first vacuum chamber, the second vacuum chamber and the third vacuum chamber are respectively provided with a reinforcing rib structure, wherein: The second vacuum chamber includes a second thin-walled tube, one side of the second thin-walled tube facing the third vacuum chamber is a second tube side plate without reinforcing rib structure, and the remaining three surfaces of the second thin-walled tube are provided with at least one second longitudinal reinforcing rib extending along the length direction of the second vacuum chamber and a plurality of second transverse reinforcing ribs perpendicular to the second longitudinal reinforcing rib; The third vacuum chamber includes a third thin-walled tube, one side of the third thin-walled tube facing the second vacuum chamber is a third tube side plate without reinforcing rib structure, and the remaining three surfaces of the third thin-walled tube are provided with at least one third longitudinal reinforcing rib extending along the length direction of the third vacuum chamber and a plurality of third transverse reinforcing ribs perpendicular to the third longitudinal reinforcing rib; The second tube side plate and the third tube side plate form an equidistant structure gap.

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